The impact on both the environment and operator health is significant. As high-alumina silica glass finds applications in smart devices such as curved mobile phone screens, the…
Abstract
Purpose
The impact on both the environment and operator health is significant. As high-alumina silica glass finds applications in smart devices such as curved mobile phone screens, the grinding of complex curved surfaces necessitates cleaner and more efficient cooling and lubrication methods to enhance processing quality and improve grinding yield rates. This study aims to focus on grinding high-alumina silica glass using micro-lubrication technology and compares its performance with traditional cutting fluid cooling methods.
Design/methodology/approach
In the fabrication of mobile phone cover plates composed of high-alumina silicon glass, the incorporation of micro-lubrication grinding technology was undertaken, with the conventional cutting fluid cooling approach serving as the benchmark control group for comparative analysis.
Findings
The results indicate that increasing the spray pressure of micro-lubrication within a specific range contributes to reducing grinding surface roughness. At a grinding speed ranging from 25 to 35 m/s, using micro-lubrication can effectively replace the traditional cutting fluid cooling method, resulting in glass surfaces with roughness levels between 0.22 and 0.26. However, at grinding speeds exceeding 35 m/s, the insufficient pressure of the micro-lubricant mist hinders most of the oil mist from entering the grinding zone, leading to inferior cooling performance compared to cutting fluid cooling. Notably, at a grinding speed of 35 m/s, micro-lubrication demonstrates better effectiveness in suppressing chipping during glass grinding compared to traditional cutting fluid cooling methods.
Originality/value
Through the application of micro-lubrication grinding technology, a marked improvement in the grinding quality of high-alumina silicon mobile phone cover plate glass can be achieved, leading to a reduction in surface roughness, a decrease in processing defects and ultimately satisfying the demands for high-precision and high-quality fabrication of such cover plates.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2024-0297
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Jiafeng Lu, Xiaolin Deng, Jing Tang and Xiaoyun Chen
When processing 11Cr-3Co-3W martensitic heat-resistant steel, the traditional pouring cooling method often appears large cutting force, high cutting temperature, serious tool wear…
Abstract
Purpose
When processing 11Cr-3Co-3W martensitic heat-resistant steel, the traditional pouring cooling method often appears large cutting force, high cutting temperature, serious tool wear and poor surface quality. This paper aims to use new cooling methods for processing this problem.
Design/methodology/approach
Different performance indicators such as cutting force, tool wear and surface quality were measured and analysed under different continuous milling times. The relationship between liquid nitrogen flow and cutting force and surface roughness was analysed and measured.
Findings
The results show that with the increase of liquid nitrogen flow, the cutting force decreases, especially the Fx component, which decreases by 10%. When the liquid nitrogen flow reaches 8 L/min, the effect of increasing the liquid nitrogen flow on reducing the cutting force becomes smaller. The cutting force reduced by up to 15%, and the tool life increased up to 20% using liquid nitrogen cryogenic cooling than in cutting liquids cooling. When minimal quantities of lubricant (MQL) was added, the cutting force was reduced by 23%, and the tool life increased by 25%. When the cutting speed increases from 100 m/min to 250 m/min, the cutting force with cutting liquid cooling does not change significantly while the cutting force with liquid nitrogen cooling decreases with the cutting speed increasing. It shows that liquid nitrogen cooling is more suitable for high-speed machining. After the cutting length reaches 66 m, the surface roughness of the workpiece using liquid nitrogen cooling method larger than that of the cutting liquid cooling method. When MQL is added into liquid nitrogen, the lubrication performance is improved, and the surface roughness of the workpiece is reduced about 8%.
Originality/value
Many studies had focused on the improvement of tool life and surface quality by different cooling methods, or on the injection process and chip mechanism. However, there are few relevant studies on the variation of cooling and lubrication properties with the change of cutting length in liquid nitrogen cryogenic processing. In this research, different performance indicators such as cutting force, tool wear and surface quality were measured and analysed under different continuous milling times. The relationship between liquid nitrogen flow and cutting force and surface roughness was analysed and measured.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2023-0053/
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Although the use of online technology has generated excitement over its potential to increase access to education, most existing research has focused on comparing online and…
Abstract
Purpose
Although the use of online technology has generated excitement over its potential to increase access to education, most existing research has focused on comparing online and in-person student performance. This study provides empirical evidence that semiprivate space at the family level affects students' access to online education.
Design/methodology/approach
Students from 1,565 low-income households in China were surveyed, and a multivariate logistic regression analysis was conducted on the hypothesized factors that affect access to online education at home.
Findings
The results show that the absence of computers, smartphones and broadband networks at home severely hinders children's access to online education, and even leads to their exclusion from it. Children with their fathers or paternal grandfathers as guardians have a lower probability of receiving online education at home. It was also found that the higher the education level of the head of the household, the more likely it is that children will receive online education at home.
Originality/value
This study is one of the first to examine online accessibility at the family level. It also demonstrates that the semiprivate space at the family level may limit opportunities for students who would otherwise pursue online education at home.
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The study aims to investigate the relationship between chief executive officers' (CEOs') prenatal testosterone exposure, absorptive capacity and e-commerce adoption by small and…
Abstract
Purpose
The study aims to investigate the relationship between chief executive officers' (CEOs') prenatal testosterone exposure, absorptive capacity and e-commerce adoption by small and medium-sized enterprises (SMEs).
Design/methodology/approach
Based on a study of 1,519 SMEs led by a male CEO in China, the impact of entrepreneur's digital ratio on e-commerce adoption is empirically analyzed through a multivariate logistic model.
Findings
The results show that the second-to-fourth digit ratio (2D:4D), a reverse measurement of prenatal testosterone exposure, is negatively correlated with the adoption of e-commerce by SMEs. This evidence suggests that CEOs with high prenatal testosterone exposure have a higher probability of adopting e-commerce. In addition, this research indicates a positive correlation between absorptive capacity, which is defined by market innovation, process innovation and marketing innovation, and the adoption of e-commerce by SMEs.
Originality/value
This research can contribute to the discussion by providing new insights into the antecedents of the adoption of e-commerce in SMEs.
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Shenlong Wang, Kaixin Han and Jiafeng Jin
In the past few decades, the content-based image retrieval (CBIR), which focuses on the exploration of image feature extraction methods, has been widely investigated. The term of…
Abstract
Purpose
In the past few decades, the content-based image retrieval (CBIR), which focuses on the exploration of image feature extraction methods, has been widely investigated. The term of feature extraction is used in two cases: application-based feature expression and mathematical approaches for dimensionality reduction. Feature expression is a technique of describing the image color, texture and shape information with feature descriptors; thus, obtaining effective image features expression is the key to extracting high-level semantic information. However, most of the previous studies regarding image feature extraction and expression methods in the CBIR have not performed systematic research. This paper aims to introduce the basic image low-level feature expression techniques for color, texture and shape features that have been developed in recent years.
Design/methodology/approach
First, this review outlines the development process and expounds the principle of various image feature extraction methods, such as color, texture and shape feature expression. Second, some of the most commonly used image low-level expression algorithms are implemented, and the benefits and drawbacks are summarized. Third, the effectiveness of the global and local features in image retrieval, including some classical models and their illustrations provided by part of our experiment, are analyzed. Fourth, the sparse representation and similarity measurement methods are introduced, and the retrieval performance of statistical methods is evaluated and compared.
Findings
The core of this survey is to review the state of the image low-level expression methods and study the pros and cons of each method, their applicable occasions and certain implementation measures. This review notes that image peculiarities of single-feature descriptions may lead to unsatisfactory image retrieval capabilities, which have significant singularity and considerable limitations and challenges in the CBIR.
Originality/value
A comprehensive review of the latest developments in image retrieval using low-level feature expression techniques is provided in this paper. This review not only introduces the major approaches for image low-level feature expression but also supplies a pertinent reference for those engaging in research regarding image feature extraction.